1. Field of the Invention
The present invention relates to a compound transistor type inverter.
The compound transistor type inverter is a so-called BiMOS transistor type inverter which is a combination of at least one bipolar transistor and at least one metal insulator semiconductor (MIS) transistor, as will be explained hereinafter with reference to the related figures. The inverter comprised of the thus-combined transistors produces advantages inherent to both the bipolar and MIS transistors, simultaneously, and thus has recently been used in practical application.
2. Description of the Related Art
The prior art compound transistor type inverter has an improved output characteristic in comparison with a conventional MIS transistor type inverter. That is, the output from the compound transistor type inverter has a quicker rise and fall than that of the MIS type inverter.
Recently, however, it has been found that the improvement in the output by the prior art of the compound transistor type inverter is now insufficient to cope with a high speed logic device, and further, the prior art inverter of the same type has a poor output stability, especially, when desiring to obtain a sufficiently low "L" level where the related output terminal is provided with a current source, as will be mentioned in detail hereinafter.